Query scheme

Executing the example shows what a query result looks like:

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Query result

<hitlist>
    <columns>
       <column name="revisions" type="revision"/>
    </columns>
    <hits>
       <hit>
          <item>
             <revision ...>
                ...
             </revision>
          </item>
       </hit>
       <hit>
          <item>
             <revision ...>
                ...
             </revision>
          </item>
       </hit>
    </hits>
 </hitlist>

A query result is a list of hits organized in named columns. Think of it as a table, or a result from an SQL query. The soap response begins with a definition of the returned columns and the types they contain, called the query scheme, followed by the actual hits.

In this instance, the query scheme has one column called “revisions” containing objects of type “revision”. This is a general convention and applies to all RAQL galaxies.

The scheme of a galaxy query has one column named after the galaxy. Each hit represents one object in the system.

Notice the type of the column: Each object and every expression in RAQL is typed. Attempting to compare objects of different types or otherwise using the wrong type of object in an expression will result in a QL-01987 error.